Cheap Transciever module for 433/868 MHz

Hello,
Seeking a cheap transmitter module for data transmission in the band 433/868MHz.
My current choice is nRF905
nRF905
and module form china
Unfortunately, the have sensitivity only -100dBm.

Can you advise something similar with better sensitivity?

If you need "a better sensitivity", check your SYSTEM design. Output power of the transmitter and antenna gains are more important in addition to receiver sensitivity.

The input sensitivity is defined by S/N ratio over the noise floor, Pn = kTB, specified by noise figure and bandwidth.

Primarily I prefer the finished modules and there is a design, given the antenna manufacturer in the PRC.
When you hit the antenna.

Can you advise some antennas with higher gain at 433/868 MHz
Alternatively, these bands are available directional antenna?

check silicon labs chips, www.silabs.com

Again, check your system parameters. To extend the range, use higher-gain antennas. You can buy good antennas from L-com, or make your own. There are simple Yagi antennas, you can use a dipole with a corner reflector, parabolic dish, flat-patch antennas, and more.

If you communicate by high data rates, it calls for a wider bandwidth, and the noise floor is higher, reducing receiver sensitivity. What is the noise figure and bandwidth of your receiver?
Again, check your SYSTEM parameters

You're right, but
IC with sensitivity -100dBm and big expensive 9dBm antenna (433MHz) will have the same sensitivity as the s the IC with sensitivity -109 dBm and a mini Antennas 0bBm.

An antenna with 9 dB gain is never BIG-imagine a 10 element Yagi at 433 MHz!
The worst problem looks to me that you have no clear idea about your system parameters. Antenna gain is measured in dB. The term dBm is for signal level related to one milliwatt.

dBm is a typo.
Antena on 433MHz with 9dB can be a whip
If I understand the original interviewer so he goes on
-primarily finished module, which would be better than, for example this
-secondarily requires the availability of IC used in the future could all be integrated on one PCB

What do you mean 9 dB whip - is it a joke?
You can not make 9 dB whip.
You can possibly make colinear array with 9 dBi gain but it will be ... some 3 m long?

Please stop arguing- we try to advise you what best to do.Follow the advice if you need to succeed.

460-480 MHz 9dBi Omni Antenna